Specialty Tea Stores?

Hello everyone, another question from me
So I recently got the starter pack at Den’s Tea, and I very much enjoy their tea, but also their business structure, the fact that it sells only Japanese Green Teas, and is almost unanimously hailed as the best Japanese Green Teas.
So are there other tea suppliers like Den’s, that is known to have the best tea of a certain type?

Teajo teas mentioned recently that they use Assam for all their flavoured blacks and I assume there are unflavoured ones as well. I haven’t had any of theirs but I do see a lot of love for them on Steepster.